It has a json schema, that’s the main point. It also enforces good documentation by design. No need to get a man page or run the help command, it’s in the context. It can work remotely with authentication.
Most CLI tools have JSON support. Your arguments fall flat pretty short.
I think MCP is fine in an env where you have no access to tools, but you cannot ripgrep your way through an MCP (unless you make an MCP that calls ripgrep on e.g. a repo, which in that case what are you doing).
Tool calls can have JSON schema enforced on lower level (token sampling). Although, I'm not sure if major providers do it, but I don't see any reason why they wouldn't.
I am not sure I agree on your statement about most CLI tools having JSON support. First, I’m not sure it’s true. But most are for sure not coming with JSON schemas for inputs and outputs.
I think MCP is fine in an env where you have no access to tools, but you cannot ripgrep your way through an MCP (unless you make an MCP that calls ripgrep on e.g. a repo, which in that case what are you doing).